Since its introduction nearly forty years ago, Mosher's acid (2-methoxy-2-triflouromethylphenylacetic acid 1), (1) and the corresponding acid chloride (2) have found increasing use as agents for determining the enantiomeric excess of amines and alcohols by NMR and other methods (2).

Other reagents are needed that can be used to determine the stereochemistry of other chiral compounds, particularly those that do not react well with Mosher's acid.